Malaria is an infectious disease that is caused by Anopheles mosquitos. The insect bite introduce the parasite (Plasmodium) into a person´s blood. There are five species of Plasmodium that can cause this disease, but Plasmodium vivax and Plasmodium falciparum are the most dangerous. This disease is mainly present in Sub-Saharan Africa, Latin America or Southeast Asia.
About 10-15 days after infection a variety of symptoms appear: fever, headache, vomiting and chill. If not treated within 24 hours, malaria con progress to severe illness and death. In children, it is frequently to develop severe anaemia, respiratory distress in relation to metabolic acidosis or cerebral malaria. In adults, multi-organ failure, immunity and asymptomatic infections, is common.
In 2017, there were an estimated 219 million cases of malaria around the world.
Can cannabinoids help to treat and fight malaria?
The marijuana plant produces several compounds, including two majors cannabinoids: Tetrahydrocannabinol (THC) and Cannabidiol (CBD). In the last ten years, cannabinoids have emerged as modulators of the central nervous system and the immune system, acting through the endocannabinoid system.
In this neuroprotective scenario and together with the antimalarial drugs, it would be an interesting strategy for the improvement of the neurological outcome in humans. Besides, the potential of cannabis to reduce pathogenic manifestation of malaria disease has special interest for the scientific community.
Recent evidence and effectiveness
Neuromalaria or cerebral malaria is the most common form of Plasmodium infection complication. It can lead to irreversible neurological and behavioural deficits, being responsible for more than 80% of lethal cases.
A 2015 study examined cerebral malaria in an animal model and the effect of cannabiniol over the cognitive function. In this work, female mice were infected and treated with CBD for 7 days, and on the 5th day-post-infection (at the highest moment of the disease), rodents received a conventional antimalarial treatment. The rodents were subjected to memory and anxiety-like-behaviors test, at the peak or after the complete clearance of the disease. Brain Inflammatory factors (TNF-alfa/IL-6), and nerve growth proteins (brain-derived neurotrophic factor, BDNF) were measured.
The results showed that rodents treated only with antimalarial drugs, had memory deficits and exhibit increased anxiety-like-behaviors, whereas mice treated with CBD did not. In addition, mice treated with CBD had a neuroprotective effect, involving a regulation of brain cytokines and an increases of BDNF levels, which might be useful to prevent neurological symptoms. Nevertheless more studies are needed to determinate the mechanism involved.
In Nigeria, marijuana ingestion of dried leaves, seeds and twigs has been claimed to protect against malaria.
In 2018, an article evaluated the effects of whole cannabis consumption on malaria-infected host. Thirty mice were inoculated with Plasmodium. Cannabis diet formulation were prepared base on standard mice diet and on weighted percentages of dried cannabis. The cannabis diet formulation was 40%, 20%, 10% and 1%.
The animals were separated in groups, comprising a group with only conventional antimalarial treatment and different groups of animals fed with cannabis diet formulation (40%, 20%, 10% and 1%.). Animals were fed, as much or as necessary for 14 days. The presence of the parasite in blood and survival rates were evaluated. The results showed a significant suppression of the parasites in the day-4 in the group of animals fed with 40% C. sativa diet formulation, as well as in the animals treated with the antimalarial drug.
Additionally, C. sativa ingestion, at the right dose, increases the survival of infected animals, although it was not as effective as the antiparasitic drug. In conclusion, C. Sativa displayed mild protection against malaria parasite activity in vivo, it is not curative, but it may mediate a disease tolerance effect during malarial infection. However, further research is needed to identify which constituents of cannabis may have mediated the benefits described in this study.
These studies have shown the multiple properties of cannabinoids as an alternative antimalarial therapy, in any case, new scientific studies will have to be carried out.
 Campos, A. C., Brant, F., Miranda, A. S., Machado, F. S., & Teixeira, A. L. (2015). Cannabidiol increases survival and promotes rescue of cognitive function in a murine model of cerebral malaria. Neuroscience, 289, 166–180.doi:10.1016/j.neuroscience.2014.12.051
 Akinola, O. et alt. (2018). Oral Ingestion of Cannabis sativa: Risks, Benefits, and Effects on Malaria-Infected Hosts. Cannabis and Cannabinoid Research, 3(1), 219–227. doi:10.1089/can.2018.0043